The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Many valve design have closure members that must provide a seal with respect to fluid flowing through the valve. Butterfly valves are one such valve, which provides a sealing structure utilizing a closure member that is rotatable about the axis of an actuator. Various butterfly valves have included valve closure members that are designed to provide for a better seal between the closure member and the seat surface. However, butterfly-type valves have a tendency for fusion to occur between the materials used for the closure member and the seat surface when the two structures are in engagement with each other, such that the closure member requires significant torque to open the valve.